It is a recognized practice to apply serving line to the power cables and bowstrings of compound bows, particularly center servings and end servings.
The compound bow uses a series of pulleys (or eccentrics) attached to the ends of the bow limbs. This design allows for increased arrow velocity and reduced force needed to hold the bow at full draw.
However, one concern with a compound bow is that increased wear and reduced life of the bowstrings and buss cables may occur. The increased load pressure applied to the end servings as they are bent by the eccentrics can result in separation of the end servings which can leave the string unprotected and subject to increased wear. Such wear can be even more evident with a single cam bow and high performance twin cam bows because these cam results in even higher load pressure and bending where the high points or steep angles on the eccentric (or cam) contact the end servings.
Typically, a bowstring is assembled from multiple strands and displayed in position for applying serving line to the nock and loop end areas. Such a procedure is described in “Making A Bowstring” Archer's Digest, 5th Edition, 1991, DBI Books.
Servings are typically made of two or more strands of material which are either twisted or braided. They are made from a variety of materials including fishing line material, polyethylene fiber material such as that available under the tradename of SPECTRA®, DACRON® polyester, and KEVLAR® poly-paraphenylene terephthalamide (aramid fiber). The servings are typically applied over the bowstring and/or power cable in a circumferential side-by-side fashion. Center servings and end servings may be applied to the bowstring and/or power cable.
Bowstrings and power cables are typically made using one of two methods. One method consists of laying out multiple strands of a given length of material and then dividing that material at the ends into two or more equal bundles and twisting or braiding these bundles into one single string or rope-like structure. The rope-like structure which is then brought back on itself and is braided or twisted back into the original material to form an end loop.
Power cables, for a single cam system, for example, may be formed by laying out a plurality of strands which are braided or twisted, folding it in half, and then wrapping an end serving around the end loop as well. Power cables for a single cam system also will typically have two smaller loops at the opposite end of the large loop, each of which will also have a small serving.
FIG. 1 from U.S. Pat. No. 6,253,754, the entire content of which is incorporated by reference herein, illustrates a prior art end serving As can be seen, a plurality of strands of bowstring material in a single string or rope-like structure has been brought back on itself to form the end loop 22. An end-serving 12A, has been wrapped around all of the strands in a side-by-side fashion. The serving material is wrapped as tightly as possible. Even though serving material is wrapped very tightly, it is susceptible to separation 23 as bowstring 12 stretches and is subject to the high load pressure of the eccentric. Once separation occurs, the bowstring fibers are left unprotected from the elements and the individual strands of the bowstring can become exposed to dirt and/or dust which can get between the individual strands and eventually wear by the eccentric. The separation is unsightly and, left unprotected, bowstring 12 can become worn and break.
Another method employed may be referred to in the art as an endless string. Using this method, a continuous strand of bowstring material is wrapped around two posts spaced apart at a distance which is approximately equal to that desired for the final bowstring length. The string is wrapped around the two posts until the desired number of strands is reached. The starting and ending point of the string is then tied together forming a splice. A separate piece of bowstring material is then typically wrapped or served over the area of the splice and end loops are formed by folding the served area back on itself and continuing to serve or wrap over the two sides of the string resulting in one multi-stranded bowstring with a loop at each end. The bowstrings thus made are usually held at one end while the other end is rotated to add twists to the main body of the string to bring the overall string length to a desired dimension that will result in the proper functioning of the bow on which the string is to be used.
U.S. Pat. No. 4,957,094, the entire content of which is incorporated by reference herein, discloses buss cables and bowstring which form a continuous length with looped ends.
The information described above is not intended to constitute an admission that such information referred to herein is “prior art” with respect to this invention.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.